Apparatuses and Methods For Toxic Gas Detection and Disabling of Toxic Gas Emission Sources

ABSTRACT

A disclosed method of detecting and terminating a source of toxic gas emission includes: detecting a gas concentration level in a zone exceeding a threshold; calculating a time weighted average gas concentration level within the zone; determining that the gas concentration level in the zone has exceeded the time weighted average gas concentration; and disabling a gas emitting source in response to determining that the gas concentration level in the zone has exceeded the time weighted average gas concentration.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to U.S. Provisional Patent Application No. 63/348,568, filed Jun. 3, 2022, entitled “APPARATUSES AND METHODS FOR TOXIC GAS DETECTION AND DISABLING OF TOXIC GAS EMISSION SOURCES” which is hereby incorporated by reference herein in its entirety, and which is assigned to the same assignee as the present application.

FIELD OF THE DISCLOSURE

The present disclosure relates generally to toxic gas detection and more particularly to methods and apparatuses for preventing emission of toxic gas.

BACKGROUND

The combustion of fossil fuels such as coal, petroleum, natural gas, etc. can result in emission of carbon monoxide. Because carbon monoxide is an odorless, tasteless and colorless gas, it is not detectable by human senses. Indoor heating systems and other indoor systems that utilize fossil fuels can develop faults in which the emission of carbon monoxide occurs at concentrations that can be harmful or fatal to humans and result in carbon monoxide-related poisoning or death.

For such indoor systems, carbon monoxide emissions may be distributed by the accumulation of carbon monoxide at the source in high concentrations that spread over time by dispersion or diffusion throughout the building such as a residential home or office building. Depending on the volume of carbon monoxide emissions and other conditions, the dispersion may result in an “uphill” dispersion or diffusion in which gas concentrations at certain locations, such as within a room, may become higher than at the source of emission resulting in potentially fatal concentrations. Carbon monoxide may also be distributed through a heating ventilation and air-conditioning (HVAC) duct and ventilation system.

Current systems for carbon monoxide detection employ a reactive distributed approach where carbon monoxide detectors are placed near the fuel burning sources such as furnaces, water heaters, clothes dryers, etc. and in hallways near each room or, depending on the configuration of the home or building, placed within each room.

Having carbon monoxide detectors located near appliances only protects against the distribution of carbon monoxide over time from a source (i.e. an appliance, furnace, etc.), but does not protect against distribution of carbon monoxide through a HVAC duct and ventilation system. Depending on the type of carbon monoxide detector used, an alarm will either be local to the detector or, if the detector is connected to an alarm system the alarm will be sent to a central collector and forwarded to a monitoring agency.

For protection against carbon monoxide poisoning in homes, consumer carbon monoxide detectors must be certified by Underwriters Laboratories Inc. (UL) and comply with the UL 2034 standard. Carbon monoxide detectors that are UL 2034 compliant are required to provide an alarm when carbon monoxide concentrations are at 30 ppm (parts per million) for 30 days or 70 ppm for one hour. A UL 2034 compliant carbon monoxide detector is not allowed to alarm if the detected level of carbon monoxide is less than 30 ppm. Some fire department jurisdictions will evacuate a home or other building if the carbon monoxide concentration level detected is at 35 ppm. Carbon monoxide concentration levels of 35 ppm are harmful for healthy adults and are even more detrimental to the health of anyone with a compromised immune system, pregnant women, the elderly, babies, and pets.

Business, commercial and industrial facilities use an approach different from residential systems by employing a combination of various types of carbon monoxide detectors that send alarm signals to a master station upon detection of harmful carbon monoxide levels. Some of the carbon monoxide detectors may be similar to those used in homes such as those that may be ceiling mounted in rooms within a building. More rugged detectors may be mounted on walls in parking garages, and yet other types of carbon monoxide detectors may use air-sampling tubes installed in ceilings for example, that route sampled air to a central carbon monoxide detector. Still other types or carbon monoxide detectors may be installed directly within ventilation systems.

All of these various types of carbon monoxide detectors send their respective alarm signals to a centralized controller that provides notifications of alarm conditions. The response to alarm conditions involves the dispatch of crews to assess the situation, and disable any sources of carbon monoxide production that are causing the alarm condition. Although in some parking garage installations carbon monoxide detectors may turn on fans when certain carbon monoxide thresholds are reached, no actions are taken to disable carbon monoxide producing sources without the assessment of human staff present at the location of the alarm condition.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a toxic gas detection and termination system in accordance with various embodiments.

FIG. 2 is a block diagram of a toxic gas detection and termination apparatus in accordance with various embodiments.

FIG. 3 is a flow chart showing operation of a toxic gas detection and termination system in accordance with various embodiments.

FIG. 4 is a flow chart showing operation of a toxic gas detection and termination apparatus in accordance with various embodiments.

DETAILED DESCRIPTION

Briefly, the disclosed apparatuses and methods are operative to detect toxic gas concentrations in various indoor zones resulting from uphill diffusion from a source as well as from or within HVAC duct systems. The disclosed apparatuses and methods are operative to identify the toxic gas emission source and disable it in response to detecting problematic concentrations within a zone.

A disclosed apparatus is operative to evaluate a concentration level of toxic gas at each sensor of a plurality of sensors, to determine if toxic gas thresholds are exceeded. The apparatus is operative to actively turn off the power to one or more of the toxic gas sources. The disclosed apparatus is operative to detect that an instantaneous toxic gas concentration threshold has been exceeded at any of a plurality of toxic gas detectors and, in response, begin calculating a time weighted average toxic gas concentration to eliminate false positives (i.e. false alarm conditions). If the toxic gas level exceeds the time-weighted average, the apparatus is operative to disable power inputs to one or more of the toxic gas sources.

One disclosed method of detecting and terminating a source of toxic gas emission, includes: detecting a gas concentration level in a zone exceeding a threshold; calculating a time weighted average gas concentration level within the zone; determining that the gas concentration level in the zone has exceeded the time weighted average gas concentration; and disabling a gas emitting source in response to determining that the gas concentration level in the zone has exceeded the time weighted average gas concentration.

The disclosed method may further include: determining that a gas concentration level in a ventilation duct has exceeded the time weighted average gas concentration; and disabling a gas emitting source corresponding to the ventilation duct in response to determining that the gas concentration level in the ventilation duct has exceeded the time weighted average gas concentration. The disclosed method may further include: determining that the gas concentration level in the zone has exceeded the time weighted average gas concentration where the zone is near a first and second gas emitting source; determining that a gas concentration level in the ventilation duct has exceeded the time weighted average gas concentration where the ventilation duct is associated with a third gas emitting source; disabling the first, second and third gas emitting sources. The disclosed method may further include: determining that a gas concentration level in the zone has exceeded the time weighted average gas concentration where the zone corresponds to a gas exhaust system; and disabling a gas emitting source corresponding to the gas exhaust system in response to determining that the gas concentration level in the zone has exceeded the time weighted average gas concentration.

A disclosed apparatus includes: toxic gas detection logic that has a plurality of inputs to receive gas concentration levels from a plurality of gas detectors and a control signal output. The toxic gas detection logic is operative to: calculate a time weighted average gas concentration level based on gas concentration level inputs received from the plurality of gas detectors; and determine that the gas concentration level detected by at least one of the gas detectors has exceeded the time weighted average gas concentration. The disclosed apparatus further includes gas source control logic that is operatively coupled to the toxic gas detection logic to receive a control signal therefrom. The gas source control logic is operative to disable a gas emitting source in response to the control signal received from the toxic gas detection logic.

Turning now to the drawings wherein like numerals represent like components, FIG. 1 illustrates a toxic gas detection and termination system in accordance with various embodiments. A toxic gas detection and termination apparatus 100 is operatively coupled to various gas detectors 110 which are divided to cover various gas detection zones 112. The detection zones may be rooms in a home or office building, the locations of one or more gas emitting sources, or ducts in a HVAC system. Ducts may be ventilation, heating or cooling ducts, or exhaust ventilation ducts that ventilate exhaust gases away from a gas emitting source. Each of the gas detection zones 112 may have one or more gas detectors 110 and may be associated with one or more gas emitting sources 104.

The toxic gas detection and termination apparatus 100 includes toxic gas detection logic 101 and gas source control logic 103 which is operatively coupled to the toxic gas detection logic 101. The toxic gas detection logic 101 receives inputs from each gas detector 110 of each gas detection zone 112. The gas source control logic 103 is operatively coupled to one or more power sources 106 and to one or more gas sources 104. The gas source control logic 103 receives a power connection 105 from each of the power sources 106 and provides a switched power output 107 to each gas emitting source 104 that receives its power from a particular power source 106. The power sources may be AC or DC power supplies.

The toxic gas detection logic 101 is operative to evaluate a gas concentration level detected by each gas detector 110 and to determine if the gas concentration level detected exceeds a threshold. If the threshold is exceeded, then the toxic gas detection logic will send a control signal to the gas source control logic 103 which will actively turn off the power to one or more of the gas emitting sources 104. The toxic gas detection logic 101 first detects when the instantaneous gas concentration level exceeds a threshold at any of the various gas detectors 110. For example, the gas concentration threshold may be 30 ppm or 35 ppm or may be between 30 ppm and 35 ppm. Once the instantaneous gas concentration exceeds the threshold, the toxic gas detection logic 101 will initiate calculating the gas concentration over a period of time as a time weighted average, to eliminate false positives. If the gas concentration at any gas detector 100 exceeds the time weighted average gas concentration level, then the toxic gas detection logic 101 sends a control signal to the gas source control logic 103 to disable the gas source.

For example, if a gas detector 110 in zone #1 detects a gas concentration level at or above the threshold, the toxic gas detection logic 101 begins to calculate the time weighted average gas concentration. The toxic gas detection logic 101 may use all gas detectors 110 within zone #1 to obtain inputs for the calculation. Additionally, the toxic gas detection logic 101 may monitor the other zones, for example zones #2 through an nth zone to check whether the time weighted average is exceeded.

The toxic gas detection logic 101 may determine a time weighted average gas concentration for all zones collectively, or may calculate a time weighted average gas concentration for each zone individually. If a specific zone gas detector 110 shows a gas concentration above the time weighted average gas concentration calculated for the specific zone, all gas emitting sources 104 corresponding to that specific zone will be disabled. In the case where the time weighted average gas concentration is calculated using all zones collectively, then if the gas concentration in a particular zone is detected that is above the collective time weighted average gas concentration, the gas emitting sources 104 corresponding to that specific zone will be disabled. However, if two or more zones have gas detectors 110 indicating that the gas concentration exceeds the time weighted average gas concentration, whether determined collectively or by individual zones, the gas emitting sources 104 for all zones will be disabled.

Gas detection zones 112 may be areas near the gas emitting sources 104, rooms in a home, offices or other rooms in an office building, specific sections within ducts of HVAC systems, etc. Each gas detection zone 112 has at least one associated gas detector 110.

FIG. 2 is a block diagram of a toxic gas detection and termination apparatus 200 in accordance with various embodiments. The toxic gas detection and termination apparatus 200 includes toxic gas detection logic 101 operatively coupled to gas source control logic 103 and is operative to provide control signals thereto. The toxic gas detection logic 101 has a series of inputs 111 to receive gas concentration levels or alarms from two or more gas detectors. The gas source control logic 103 has a series of inputs 105 to receive power signals for switching the gas emitting sources off via a series of power on/off signal outputs 107. The power switching may be implemented via electromechanical relays or via power transistor circuits that are operative to switch current flow off to the various power inputs of the gas emitting sources.

In some embodiments, the toxic gas detection and termination apparatus 200 may further include an event recorder 115 that is operative to record gas concentration levels received by the toxic gas detection logic 101, calculated time weighted averages, and control signals sent from the toxic gas detection logic 101 to the gas source control logic 103 to disable gas emitting sources. Each recorded event may include a time stamp, date stamp as well as other metadata associated with the event. The metadata may include, but is not limited to, an identifier of the gas detector that produced a given reading at a given time, a gas emitting source identifier for a gas emitting source that was disabled, etc.

In some embodiments, the toxic gas detection and termination apparatus 200 may further include a transceiver 117 operative to send and receive radio signals such as, but not limited to, cellular 3G, 4G, or 5G signals, WiFi™, Bluetooth™, etc. The transceiver 117 may be operative to establish an Internet connection wirelessly to send information from the toxic gas detection logic 101 or from the event recorder 115. In some embodiments, the transceiver 117 may be operative to receive instructions wirelessly such as settings, program code or firmware updates, etc. The transceiver 117 may include any antennas necessary for wireless communication at one or more frequency bands and using one or more communication protocols, etc. The transceiver 117 may be an Internet-of-things (IoT) device in some embodiments.

Each of the components of the toxic gas detection and termination apparatus 200 may be implemented independently or collectively, using in any combination without limitation, one or more microprocessors, ASICs, FPGAs, microcomputers, microcontrollers, digital signal processors, central processing units, state machines, logic circuitries, and/or devices that manipulate signals based on operational instructions. Power control circuitry within the gas source control logic 103 may include electromechanical relays, power transistor circuitry or the like, etc.

Processors may be configured and operative to fetch and execute computer-readable instructions (i.e. executable instructions) stored in memory (not shown). For example, in one embodiment, a single processor may be used to implement the toxic gas detection logic 101 and the gas source control logic 103 where the process accesses from memory and executes operating system executable instructions, which when executed by the processor provide a kernel, libraries (i.e. application programming interfaces or “APIs”), an application layer “user space” within which various applications may be executed, and an IP protocol stack.

In some embodiments, either or both of the event toxic gas detection logic 101 and the gas source control logic 103 may be implemented using ASICs, FPGAs, DSPs, or combinations thereof. For example, the toxic gas detection logic 101 may be implemented as an ASIC and the gas source control logic 103 may be implemented as a microcontroller that is operatively coupled to the ASIC.

In some embodiments, all of the components of the toxic gas detection and termination apparatus 200 may be operatively coupled by an internal communication bus. As used herein, components may be “operatively coupled” when information can be sent between two such components, even though there may be one or more intermediate or intervening components between, or along the connection path. Therefore, any of the various components with the toxic gas detection and termination apparatus 200 may be understood herein to be operatively coupled to each other where appropriate, and to be executing on one or more processors that are further operatively coupled to a memory that stores executable instructions (also referred to as “software code” or “code”) for implementing the various components. Operative coupling may also exist between engines, system interfaces or components implemented as software or firmware executing on a processor and such “software coupling” may be implemented using libraries (i.e. application programming interfaces (APIs)) or other software interfacing techniques as appropriate. Such libraries or APIs provide operative coupling between various software implemented components of FIG. 2 .

All of the components described herein may be implemented as software or firmware (or as a combination of software and firmware) executing on one or more processors, and may also include, or may be implemented independently, using hardware such as, but not limited to, ASICs (application specific integrated circuits), DSPs (digital signal processors), hardwired circuitry (logic circuitry), or combinations thereof. That is, any of the components disclosed herein may be implemented using an ASIC, DSP, FPGA executable instructions executing on a processor, logic circuitry, or combinations thereof. In other words, the components may be implemented as hardware, software or by combinations thereof. Therefore, each of the components disclosed herein may be independently considered a type of apparatus that may be implemented and operate independently from the other components in the system. For example, any one of the toxic gas detection logic 101, gas source control logic 103, event recorder 115, or transceiver 117 may be implemented using an ASIC, DSP, FPGA, executable instructions executing on a processor, logic circuitry, or combinations thereof.

FIG. 3 is a flow chart showing operation of a toxic gas detection and termination system in accordance with various embodiments. At operation 301, the toxic gas detection logic 101 monitors distributed gas concentration levels at various gas sources 104. The sources may be furnaces, clothes dryers, machinery etc. At operation 303, the toxic gas detection logic 101 monitors gas concentration levels within a ventilation system, such as within a HVAC duct using a duct gas detector. At operation 305, based on an input received from various gas detectors 110, the toxic gas detection logic 101 determines if an instantaneous gas concentration threshold is exceeded at any gas detector. For example, for carbon monoxide the gas concentration threshold may be 30 ppm, 35 ppm or between approximately 30 ppm and 35 ppm.

At operation 307, the toxic gas detection logic 101, in response to receiving a gas detector indication that the instantaneous gas concentration has been exceeded, determines a time weighted average of gas concentration level. This operation may be done using inputs from only the gas detectors located in the zone of the gas detector the provided the indication, or by using inputs from all gas detectors in all zones. At operation 309, the toxic gas detection logic 101 determines if any gas detector at a source or within a ventilation system detects gas concentration level greater than the calculated time weighted average of gas concentration level over a period of time. At operation 311, the toxic gas detection logic 101 sends a control signal to the gas source control logic 103 to disable one or more gas emitting sources 104 corresponding to the gas detector, or gas detectors, where the gas concentration exceeded the time weighted average. At operation 313, the gas source control logic 103 disables the one or more gas emitting sources corresponding to the gas detector the detected gas concentration exceeding the time weighted average.

FIG. 4 is a flow chart showing operation of a toxic gas detection and termination apparatus 100 in accordance with various embodiments. At operation 401, the toxic gas detection and termination apparatus 100 monitors gas concentration levels in two or more zones 112. For example, one zone may be a location near or at a gas emitting source 104 and another zone may be an HVAC duct. At decision 403, the toxic gas detection and termination apparatus 100 determines whether a gas concentration threshold level has been exceeded in any zone 112. If the gas concentration threshold has been exceeded at decision 403, then at operation 405, the toxic gas detection and termination apparatus 100 begins calculating a time weighted average gas concentration level in the first zone. If the gas concentration threshold has not been exceeded at decision 403, then the toxic gas detection and termination apparatus 100 continues to monitor the zones in operation 401.

At decision 407, after the time weighted average gas concentration level in the first zone has been calculated, the toxic gas detection and termination apparatus 100 checks whether the time weighted average has been exceeded in the first zone. If yes, then at operation 413, the toxic gas detection and termination apparatus 100 identifies the gas emitting sources for the first zone and at operation 415 disables the identified gas sources. If the time weighted average has not been exceeded in the first zone at decision 407, then the method returns to operation 401.

At decision 409, the toxic gas detection and termination apparatus 100 also checks whether the time weighted average has been exceeded in second zone. This procedure may be repeated for all zones up to the nth zone. If yes, then at operation 417, the toxic gas detection and termination apparatus 100 identifies the gas emitting sources for the second zone and at operation 419 disables the identified gas sources. If the time weighted average has not been exceeded in the second zone at decision 409, then the method returns to operation 401.

If at decision 411, the toxic gas detection and termination apparatus 100 determines that the time weighted average has been exceeded in two or more zones, then at operation 421, the toxic gas detection and termination apparatus 100 disable all gas sources for all zones. If at decision 411, the time weighted average has not been exceeded in two or more zones, then the method returns to operation 401 and continues to monitor the gas concentrations in any zones for which gas emitting sources are still operative.

While various embodiments have been illustrated and described, it is to be understood that the invention is not so limited. Numerous modifications, changes, variations, substitutions and equivalents will occur to those skilled in the art without departing from the scope of the present invention as defined by the appended claims. 

What is claimed is:
 1. A method of detecting and terminating a source of toxic gas emission, the method comprising: detecting a gas concentration level in a zone exceeding a threshold; calculating a time weighted average gas concentration level within the zone; determining that the gas concentration level in the zone has exceeded the time weighted average gas concentration; and disabling a gas emitting source in response to determining that the gas concentration level in the zone has exceeded the time weighted average gas concentration.
 2. The method of claim 1, further comprising: determining that a gas concentration level in a ventilation duct has exceeded the time weighted average gas concentration; and disabling a gas emitting source corresponding to the ventilation duct in response to determining that the gas concentration level in the ventilation duct has exceeded the time weighted average gas concentration.
 3. The method of claim 2, further comprising s determining that the gas concentration level in the zone has exceeded the time weighted average gas concentration where the zone is near a first and second gas emitting source; determining that a gas concentration level in the ventilation duct has exceeded the time weighted average gas concentration where the ventilation duct is associated with a third gas emitting source; and disabling the first, second and third gas emitting sources.
 4. The method of claim 1, further comprising: determining that a gas concentration level in the zone has exceeded the time weighted average gas concentration where the zone corresponds to a gas exhaust system; and disabling a gas emitting source corresponding to the gas exhaust system in response to determining that the gas concentration level in the zone has exceeded the time weighted average gas concentration.
 5. An apparatus comprising: toxic gas detection logic comprising a plurality of inputs to receive gas concentration levels from a plurality of gas detectors and a control signal output, operative to: calculate a time weighted average gas concentration level based on gas concentration level inputs received from the plurality of gas detectors; determine that the gas concentration level detected by at least one of the gas detectors has exceeded the time weighted average gas concentration; and gas source control logic, operatively coupled to the toxic gas detection logic to receive a control signal therefrom, and operative to disable a gas emitting source in response to the control signal received from the toxic gas detection logic.
 6. The apparatus of claim 5, wherein the toxic gas detection logic is further operative to: determine that a gas concentration level in a ventilation duct has exceeded the time weighted average gas concentration; and send a control signal to the gas source control logic to disable a gas emitting source corresponding to the ventilation duct in response to determining that the gas concentration level in the ventilation duct has exceeded the time weighted average gas concentration.
 7. The apparatus of claim 6, wherein the toxic gas detection logic is further operative to: determine that the gas concentration level in a zone has exceeded the time weighted average gas concentration where the zone is near a first and second gas emitting source; determine that a gas concentration level in the ventilation duct has exceeded the time weighted average gas concentration where the ventilation duct is associated with a third gas emitting source; and send a control signal to the gas source control logic to disable the first, second and third gas emitting sources.
 8. The apparatus of claim 5, wherein the toxic gas detection logic is further operative to: determine that a gas concentration level in a zone has exceeded the time weighted average gas concentration where the zone corresponds to a gas exhaust system; and send a control signal to the gas source control logic to disable a gas emitting source corresponding to the gas exhaust system in response to determining that the gas concentration level in the zone has exceeded the time weighted average gas concentration.
 9. An apparatus comprising: toxic gas detection logic comprising a plurality of inputs to receive gas concentration levels from a plurality of gas detectors and a control signal output; and gas source control logic, operatively coupled to the toxic gas detection logic to receive a control signal therefrom, and operative to disable at least one gas emitting source in response to the control signal received from the toxic gas detection logic.
 10. The apparatus of claim 9, wherein the toxic gas detection logic is further operative to: calculate a time weighted average gas concentration level based on gas concentration level inputs received from the plurality of gas detectors.
 11. The apparatus of claim 9, wherein the toxic gas detection logic is further operative to: determine that a gas concentration level detected by at least one of the gas detectors has exceeded a time weighted average gas concentration.
 12. The apparatus of claim 9, wherein the gas source control logic is further operative to: receive a control signal from the toxic gas detection logic, and disable at least one gas emitting source in response to the control signal received from the toxic gas detection logic. 